I redid everything, turned of the ambient measurement and did a long iterative calibration. It is starting to look like a result I can trust. Still seems slightly odd that I have to increase vibrance this much for things to appear more or less like before, but I suppose it could be right. I will have to get used to the new color environment.

I'll output some images and see how they look at my calibrated monitor at work. If they appear similar then I think I can call off any panic attacks.

Very good point. The HP LP2475 seems slower to stabilise than others I've used. Both colour and brightness take at least 30 minutes to stabilise. I recommend leaving it on for an hour before calibrating.

I have to say something about web browsers, which is where most unsuspecting wide gamut display owners trip up. At the moment there is only one browser that works satisfactorily with wide gamut displays, and that's Firefox. But you still have to modify the default configuration a bit.

Several browsers claim to be color managed, including Safari. The problem is that most content on the web is untagged (doesn't have an embedded profile), and that breaks the color management chain. There's no source profile to convert to the monitor profile from, and so those browsers just leave the material in an unmanaged state, sending the image RGB numbers straight through to the display unmodified.

Firefox has an optional configuration that assigns sRGB to any untagged material. This gets the color management machine running again. Assigning sRGB is a safe assumption since it's most likely created in sRGB with that intent. And this has the added advantage that you effectively get full color management even on untagged material, instead of "close enough" which is what you normally get.

To get there, type about:config (copy/paste that) into the address bar, and scroll down to gfx.color_management.mode. Change the value from 2 to 1, and relaunch Firefox. The beauty of this setting is that it affects the whole works, page elements as well as images. Everything appears correctly.

(and while you're there, you can enable v4 monitor profiles as well, in case you should ever need that).

Several browsers claim to be color managed, including Safari. The problem is that most content on the web is untagged (doesn't have an embedded profile), and that breaks the color management chain. There's no source profile to convert to the monitor profile from, and so those browsers just leave the material in an unmanaged state, sending the image RGB numbers straight through to the display unmodified.

IE9 and 10 use sRGB for untagged images, which is exactly what you would want in almost every case. What they do not do is use the monitor profile, which makes viewing on a wider gamut monitor interesting.

Firefox for me, came with color mode set to one (full color management), but with ICC v4 dissabled.

Agreed. If the monitor happens to be exactly sRGB in colour space and TRC then IE will display correctly. But even monitors with an sRGB mode and factory calibration are rarely very accurate. As you say, slim chance of accurate colour with IE.

It's bonkers. Microsoft go to all the trouble of implementing colour management in IE, but use only the image profile and don't bother with the monitor profile. They've implemented 99% of the functionality of colour management, but by missing the 1% (looking up monitor profile) they virtually rule out the possibility of accurate colour.

Actually IE does in fact have full color management - all the code is there and happily churning along. It does convert from a source profile to a monitor profile, as it should. But then some brilliant engineer said "hey, let's not use the actual monitor profile, let's use sRGB!". And they all said yeah, whatever...

This is very likely the stupidest decision in the entire history of computing. It's all there, and then they deliberately broke it.

For wide gamut users it means everything comes in psychedelic technicolor, no exception. Even an Adobe RGB image, which could otherwise pass without too much comment. For everyone else it's no color management, tagged or not. Unless you happen to have a monitor that matches sRGB exactly, of course.

And so I brought a few adjusted Tiffs with me to work and had a look. The photos actually look closer to the ones at home than I had expected. Clearly not identical but at least not miles apart. And a lot better from the calibration with no ambient light on.

So that is good at least! The real test will be to have a professional print made. I feel unable to tell anything for certain at the moment. Even after taking a break for a week I am equally confused about what to trust.

The calibrated display appears to me to have a bit too low contrast and saturation. Everything looks wrong and this has put me off working with photography altogether for now. The histogram just doesn't feel right to me.

I suppose when I get a print, I can increase contrast and saturation a bit if needed. No matter what the Spyder says, what matters is what ends up framed on the wall.

But I hate this feeling of having lost years of photo adjustments. And not having any confidence in what I am actually outputting now. Despite clearly not knowing anything about anything, I actually work as an image editor for a company. And even at work now I feel increasingly color blind when I tweak those skin tones. It is driving me crazy. I stand waiting for my tram to work and I mentally color correct people around me. They all look off.

I propose the need for a new medical term, something like Digital Chromatosis; -the lack of color confidence, the inability to correctly adjust skin tones and/or the sensation when returning to your desk after a break of seeing that the image on screen is horribly over edited.